Lathe-dog.



PATENTED NOV. 26, 1907.

R. G. NYE.

LATHE DOG.

APPLIOATION FILED M312, 1906.

W/ T/VE 55515 I ROBERT G. NYE, OF OSWEGO, NEW YORK.

LATHE-DOG.

I Specification of Letters Patent.

Patented Nov. 26, 1907'.

Application filed February 12. 1906. Serial No. 300,742.

To all whom it may concern:

Be it known that 1, ROBERT G. NYE, of Oswego, in the county of Oswego,in the State of New York, have invented new and useful Improvements inLathe Dogs, of which the following, taken in connection with theaccompanying drawings, is a full, clear, and exact description.

This invention relates to improvements in lathe dogs in which two jawsare adapted to grip opposite faces of the work to be held in proximityto the face plate of a lathe, one of the jaws having a suitabletail-piece engaging in an aperture in said face-plate, whereby rotarymotion is transmitted from the face plate through the gripping aws tothe work.

One of the objects of my present invention is to enable the jaws to beeasily and quickly clamped upon the work and coupled to the face-platewith a greater degree. of security than is common to such devices. Thisobject, more specifically stated, is to enable the jaws to be morerapidly ad usted from the maximum to the minimum sizes of work to beclamped than would be possible with devices using screws only for suchadjustment.

Another object is to provide means for holding the clamping jaws intheir adjusted position when not attached to the work, thereby obviatingcollapse of the jaws, and expediting the labor of removing andreinserting the work between the aws.

A further object is to provide one of the jaws with a tail-piece soarranged that when applied to the face-plate it tends to tighten thegrip of the jaws upon the work.

A further object is to hold the toothed rack in engagement with thelocking shoulder under yielding pressure of a spring which allows thetoothed rack to be readily disengaged from its locking shoulder whenassembling the jaws upon the work.

Other objects and uses Wlll be brought out in the following description.

In the drawingsFigure 1 is a top plan of my improved lathe-dog shown asoperatively engaged with a face-plate and the work to be clampedthereto, the face-plate and the part of the lathe upon which thelathe-dog 1s clamped being shown by dotted lines. Fig. 2 is a frontelevation partly in section of the lathe-dog seen in Fig. 1. Fig. 3 is aside view of the same. Fig. 4 is a top plan View of the jaw having theintegral toothed rack. Fig. 5 is an inverted plan view of the other awor This lathe-dog comprises essentially two opposed jaws 1 and -2-; atoothedbar or rack-bar -3 rigidly united to the jaw 1- at substantiallyright angles thereto; a tail-piece 2 rigidly united to the jaw 2 andprojecting axially at substantially right angles thereto; a shoulder 4on the jaw for engaging the teeth 16 of the rack-bar 3; a spring -5- forforcing the teeth of the rack-bar 3 into e11- gagement with thestationary pawl -4 and a screw 6 connecting both jaws, for drawing themtogether upon the work.

The gripping faces of the jaws -1- and -2- are provided with V-shapedcutouts 7 and S for engaging the work, as for instance, a shaft 9 shownby dotted lines in Figs. 1 and 2.

The aw -1- is provided near one end with an elongated slot -10 having aflaring outer end forming a beveled seat 1 1 for receiving a conicalhead 12 of the clampin -bolt or screw 6-, which latter is provided withan angular portion 13- for receiving a wrench or similar tool by whichthe screw may be rotated. The slot 10 is substantially of the same widthas the diameter of the unthreaded shank of the bolt 6, but is ofsufficient length to permit the requisite play between the parts toenable the teeth 16 of the rack-bar 3 to be disengaged from the pawl 4when assembling the parts of the device upon or removing them from thework.

The threaded end of the bolt -6 is screwed into a threaded aperture 14in the jaw 2-, and the tapering head -12 and its taperin seat 11- afforda comparatively broad bearing to keep the jaws in more perfectalinenient when clamping the same upon the work. j 1;,

The toothed rack 3- is disposed at the side of the axis of revolutionopposite to and substantially parallel with the screw 6-, and is free toslide in an elongated opening or aperture 15 in the jaw -2, to enablethe bar to move against the action of the spring -5 to disengage itsteeth from the locking pawl 4 when placing the jaws upon or removingthem from the work. The teeth, 16 of the rack -3, are so arranged withreference to the locking pawl -4- as to resist outward radial movementof the jaws when clamped upon the work, and in this instance the lockingpawl 4- consists of a hardened steel knife-edge plate'secured bysuitable means, as a screw -17, to the outerface of the adjacent end ofthe jaw 2 so as to interpose the strength and resistance of the adjacentend of the said jaw 2* as well as the locking pawl 4 against the strainsto which the jaws are subjected when clalnped in operative position ordrawn upon the work by the screw 6.

The spring 5 is seated in a suitable socket -18- at the side of thetoothed bar -3- opposite to that having the teeth 16, and therefore,opposite the locking pawl 4 so as to yieldingly hold the toothed rack inengagement with said locking member at all times, either when the jawsare clamped upon the work, or when they are removed from it, therebykeeping the jaws in operative relation to each other ready to be clampedupon similar sized work, or they may be readily moved toward each otherupon smaller work by simply pressing them together. In this instance,the teeth 16 act as a ratchet upon the pawl -4 and the opposite end ofthe jaw -1 is free to slide upon the bolt 6, thus keeping the grippingfaces of the jaws substantially parallel, so that when broughtfirmlyupon the work, all that is necessary to do is to rotate the screw orbolt 6 (which may be done by hand) farther into the threaded socket 14,until the tapering head 12 is firmly engaged with the seat 11-,whereupon the wrench may be applied to the angular portion -l3 for morefirmly gripping the jaws upon the work.

The tail-piece 2 projects axially from the end of the jaw 2 opposite tothat in which the toothed rack 3 operates and is adapted to enter anaperture, as a, in the face plate, indicated at -A, of a lathe or othersimilar machine.

The jaws 1 and -2-; tooth-rack 3 and screw 6 are disposed insubstantially the same vertical plane trans versely of their axis ofrevolution and the tail-piece 2 projecting, as it does, from one end ofthe jaw 2-, tends when in operation, to force this end of the aw -2toward the jaw -1, and thereby pro duces a firmer grip of the jaws uponthe work, it being understood that the faceplate rotating in thedirection indicated by arrow, Fig. 1, engages the tail-piece 2 andproduces a constant pull upon the end of the jaw 2 adjacent to the clampscrew toward the jaw 1, while at the same time the opposite end of thejaw 2 being operatively connected to the toothed rack 3 tends to pullthe jaw 1 toward the jaw 2. This produces a cramping action, andconsequently firmer grip of the jaws upon the work when being rotated bythe face-plate without liability of throwing the jaws out of theircenter.

It is obvious upon reference to Fig. 3 that this lathe dog is capable ofreceiving work equal in size to the space between the screw 6 andtoothed rack 3, or any smaller work, as the jaws 1 and 2 may bebroughtinto close proximity to each other.

In operation, the work is inserted between the jaws, which are thencompressed or forced together by hand, thereby causing the teeth of therack 3 to slide across the knifeedge of the fixed pawl 4- against theaction of the spring 5, which operates to force the rack into holdingengagement with the pawl -4 as soon as the adjustment is made, afterwhich the screw 6- is tightened to more firmly grip the jaws upon thework and the tail-piece 2 is then inserted in the opening a in theface-plate A, whereupon the whole device is ready to be rotated for thepurpose desired.

WVhat I claim:

A lathe dog comprising a jaw having a threaded aperture at one end andan elongated slot at the other end, and with a tail piece extendinglaterally from the end of the jaw having the threaded aperture, a stoppawl carried by said jaw and extending into said slot, an opposing jawhaving an elongated aperture through one end and a rack-bar projectingat right angles therefrom at the other end and extending through theslot in the first mentioned jaw, a spring operating to maintain saidrack-bar yieldably in engagement with said pawl, and a screw extendingthrough the slot in said last mentioned jaw and provided with anenlarged head bearing upon the same, and engaging said threaded apertureby its threaded portion.

In witness whereof I have hereunto set my hand this 6th day of February1906.

ROBERT G. NYE.

Witnesses:

JAS. H. TAYLOR, GEO. B. HUNT.

